The invention concerns an arrangement and method for determining the oil consumption of an oil-lubricated machine, in particular, a compressive oil-lubricated machine, such as an internal combustion engine, a compressor, a turbocharger, a pump, etc.
Such an arrangement is known for example from DE 20 2005 008 511 U1, in which an oil circuit is provided which leads from the oil pan of an internal combustion motor via an outer oil tank back to the oil pan. On the basis of this forced path of the oil circuit conclusions regarding oil consumption can be drawn via a gravimetric recording of the oil volume inside the oil tank.
A disadvantage of the known oil consumption determination emerges, mainly at the beginning of the measurement procedure, i.e., during the start-up phase of the internal combustion motor, in that large measurement fluctuations arise, which permit conclusions as to the oil consumption only conditionally, especially for the start activity of the combustion motor. Such measurement fluctuations are gathered from test results which are stated in FIG. 2 of the above-mentioned DE 20 2005 008 511 U1.
Furthermore, it must be observed that the oil consumption values calculated by means of the known measuring device arrangement on the whole were lower than the actual oil consumption in ordinary operation of the internal combustion engine when empirically ascertained.
It is desirable to improve the arrangement to determine the oil consumption of an oil-lubricated machine, so that oil consumption measurement can be carried out more precisely in the start-up phase of the internal combustion engine as well.
A device for heating oil according to an aspect of the present invention is assigned to the start line in such a way that oil is heatable to a predeterminable operating temperature, which preferably corresponds to the optimal operating conditions of the machine, before reaching the machine. By heating the oil, practical conditions for oil consumption measurement are created, whereby unforeseeable measurement fluctuations still encountered in the prior art can be equalized.
For example, the heating device can be realized by means of suitable heating casings on the start line, which heat the flowing or standing oil volume in the start line until the desired operating temperature of the oil is reached.
In order, however, to provide a near-operation simulation of the oil circuit during the preheating phase as well, the oil circuit arrangement can have a bypass-line to short-circuit the start line or feed line and the return line, for example, to separate the working machine from the oil circuit. By means of the bypass line, the oil inside the oil circuit can be heated while maintaining the flow of oil, until the desired operating temperature for all oil in the oil circuit is reached. Preferably, the bypass line is connected to the start or return line upstream of the internal combustion engine via a 3-way valve. The 3-way valve can be controlled in such a way that the start line is fully blocked up to the oil-lubricated machine and the entire oil flow reaches the return line via the bypass line. In this way the entire oil volume in the start and return line and in the oil tank is heated by the heating device to the preferred prescribed operating temperature approximately equally.
In a preferred embodiment of an aspect of the invention, a temperature sensor for determining oil temperature is arranged, preferably directly upstream of the heating device, in order to provide data to a temperature regulator for regulating activation of the heating device.
Furthermore, a pressure sensor for determining oil pressure can be arranged upstream of the heating device. In the process, the pressure sensor is connected to a pressure regulator, which activates the oil pump built into the start line. In order to prevent incoming oil from flowing back into the oil tank when there are pressure fluctuations in the conduit system, preferably a non-return valve can be built into the intake line. In this way weight fluctuations in the precision balance can be avoided. With the help of this arrangement the necessary oil pressure can also be adjusted with the help of a frequency converter, which can regulate the speed of an oil pump.
Preferably, a further pressure sensor for determining oil pressure is arranged upstream of the working machine and downstream of the heating device, in order to register the effective oil pressure before the machine is reached, and to be able to control it.
In an alternative or additional implementation of an aspect of the invention, in order to increase the precision of the oil consumption determination, the generic arrangement is provided with a blow-by gas passage which is attached to the oil circuit. The blow-by gas passage should lead blow-by gas created by the machine away from the oil circuit. The oil particles contained in the blow-by gas are separated by a filtration system in order to be able to determine their weight. In normal operation, the blow-by gas would be fed back to the machine. In the invention, the weight calculated from the blow-by gas is computed, whereby actual oil consumption can be calculated.
Preferably, the blow-by gas passage discharges upstream of the combination of the bypass line and the return line, before the bypass line and the return line meet, in order to affect the oil circuit as little as possible.
In order to realize adequate diversion of the blow-by gas, preferably a blow-by gas pump is arranged in the blow-by gas passage.
In a preferred embodiment of an aspect of the invention, there is at least one filter with a specially assigned magnet valve upstream of the blow-by gas pump. Alternatively, there can be two filters connected parallel to each other, each with a specially assigned magnet valve, upstream of the blow-by gas pump.
In addition, an aspect of the invention concerns a device for determining the oil consumption of an oil-lubricated machine, in which oil is pumped in from an oil tank and out to the working machine, and from there is led back to the oil tank, whereby the weight of the oil volume found in the oil tank is continuously measured gravimetrically. According to the invention, the oil is heated before passing through the machine to a predeterminable operating temperature for the working machine.
Preferably, the oil pressure and the oil temperature are adjusted to the operating conditions of the machine, before the oil consumption determination process is initiated.
Preferably, the blow-by gases with oil particles contained therein are led to an oil circuit which leads from the oil tank to the machine and back to the oil tank.